Container-based connectivity check in software-defined networking (SDN) environments

ABSTRACT

Example methods and systems for container-based connectivity check in a software-defined networking (SDN) environment are disclosed. One example method may comprise detecting, a request for a connectivity check between a first container-based resource and a second container-based resource; identifying a first logical network element and a second logical network element; and injecting a connectivity check packet at the first logical network element for forwarding towards the second logical network element. The example method also may comprise: obtaining report information associated with one or more intermediate logical network elements located along a path that is traversed by the connectivity check packet; and determining a connectivity status associated with the first container-based resource and the second container-based resource based on the report information.

CROSS-REFERENCE TO RELATED APPLICATION

The present U.S. patent application Ser. No. 16/742,919 is related insubject matter to U.S. patent application Ser. No. 16/742,917, filed onJan. 15, 2020, and entitled “CONTAINER-BASED NETWORK POLICYCONFIGURATION IN SOFTWARE-DEFINED NETWORKING (SDN) ENVIRONMENTS,” whichis incorporated herein by reference.

BACKGROUND

Virtualization allows the abstraction and pooling of hardware resourcesto support virtual machines in a Software-Defined Networking (SDN)environment, such as a Software-Defined Data Center (SDDC). For example,through server virtualization, virtualization computing instances suchas virtual machines (VMs) running different operating systems may besupported by the same physical machine (e.g., referred to as a “host”).Each VM is generally provisioned with virtual resources to run anoperating system and applications. The virtual resources may includecentral processing unit (CPU) resources, memory resources, storageresources, network resources, etc. Further, through container-basedtechnology, multiple containers may be executed as isolated processesinside a VM. In practice, various network connectivity issues thataffect the performance of containers or pods may occur in the SDNenvironment. However, it may be challenging to perform network diagnosisusing existing tools.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating an example software-definednetworking (SDN) environment in which container-based network policyconfiguration may be performed;

FIG. 2 is a schematic diagram illustrating an example physicalimplementation view of the SDN environment in FIG. 1;

FIG. 3 is a flowchart of an example process for a computer system toperform container-based network policy configuration in an SDNenvironment;

FIG. 4 is a flowchart of an example detailed process for a computersystem to perform container-based network policy configuration in an SDNenvironment;

FIG. 5 is a schematic diagram illustrating an example configuration ofcontainer-based resources and logical network elements in an SDNenvironment;

FIG. 6 is a schematic diagram illustrating an example of container-basednetwork policy configuration in an SDN environment;

FIG. 7 is a flowchart of an example process for a computer system toperform container-based connectivity check in an SDN environment;

FIG. 8 is a schematic diagram illustrating an example of container-basednetwork policy configuration prior to a container-based connectivitycheck in an SDN environment;

FIG. 9 is a schematic diagram illustrating a first example ofcontainer-based connectivity check in an SDN environment; and

FIG. 10 is a schematic diagram illustrating a second example ofcontainer-based connectivity check in an SDN environment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe drawings, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated herein. Although the terms “first,” “second” and so on areused to describe various elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother. A first element may be referred to as a second element, andvice versa.

FIG. 1 is a schematic diagram illustrating example SDN environment 100in which container-based network policy configuration may be performed.It should be understood that, depending on the desired implementation,SDN environment 100 may include additional and/or alternative componentsthan that shown in FIG. 1. Here, computer system 110 (“containerplugin”) is configured to act as an interface between containerorchestration systems 101 (one shown for simplicity) and SDN manager 102of a virtualization platform. For example, container plugin 110 maymonitor events on container orchestration system 101 and translate theminto instructions to SDN manager 102. Any suitable network plugin may beused, such as VMware NSX® container plugin (NCP) from VMware, Inc. Inpractice, NSX® is an SDN virtualization and security platform thatdecouples networking functions from the underlying physical devices (tobe discussed further using FIG. 2).

Depending on the desired implementation, container plugin 110 mayimplement orchestrator-specific adaptor(s) 112 to interact withcontainer orchestration system 101, core infrastructure 111 andbackend-specific application programming interface (API) client(s) 113to interact with SDN manager 102. Orchestrator-specific adaptor 112 mayperiodically poll information and listen to live event streams fromcontainer orchestration system 101. Core infrastructure 111 may beconfigured to dispatch instructions to SDN manager 102, such as in theform of Representational State Transfer (REST or RESTful) applicationprogramming interface (API) calls, etc. Container plugin 110 may alsoconfigure networking interfaces for containers according to any suitablestandard, such as Container Network Interface (CNI).

Container orchestration system 101 (also known as a containerorchestration layer) may implement any suitable container technology,such as Docker Swarm®, Kubernetes®, Cloud Foundry® Diego, Apache®Mesos™, etc. In practice, Kubernetes (abbreviated as “K8s”) is acontainer orchestration platform that is designed to simplify thedeployment and management of cloud-native applications at scale.Kubernetes may be implemented to provide a container-centricinfrastructure for the deployment, scaling and operations of applicationcontainers across clusters of hosts. Since its inception, Kubernetes hasbecome one of the most popular platforms for deploying containerizedapplications. Kubernetes defines a networking model for itscontainer-based resources, while the implementation of the networkingmodel is provided by network plugins, such as container plugin 110 inFIG. 1.

As used herein, the term “container” (also known as “containerinstance”) is used generally to describe an application that isencapsulated with all its dependencies (e.g., binaries, libraries,etc.). Containers are “OS-less”, meaning that they do not include any OSthat could weigh 10s of Gigabytes (GB). This makes containers morelightweight, portable, efficient and suitable for delivery into anisolated OS environment. In practice, running containers inside avirtual machine (VM) or node not only leverages the benefits ofcontainer technologies but also that of virtualization technologies.

As used herein, the term “container-based resource” or“container-orchestrator resource” may refer to an entity or objectassociated with a containerized application that is configurable andmanageable via container orchestration system 101. Some examplecontainer-based resources are shown in FIG. 1, such as cluster (see120), master node (see 121), worker nodes (see 122-123), pods (see141-144), containers (i.e., member of a pod), namespaces, etc. UsingKubernetes for example, a cluster may include master node(s) and workernode(s). Each node may include multiple pods, each pod a group of one ormore containers that share an IP address and a data volume. Namespacesmay be configured to divide resources of a cluster amongst multipleusers and/or groups.

In practice, containers are gaining popularity as a packaging unit todeploy micro-services because of their relatively small footprintcompared to VMs. Using a micro-service architecture, an application maybe divided into multiple distinct parts that are executed independentlyfrom each other, each part being implemented using one or morecontainers. An application that is implemented using multiple containersmay be referred to as a containerized application or cloud-nativeapplication. For example, a web-based application may be broken into aweb front-end server that is implemented using front-end container(s),database server using database container(s), application server usingapplication container(s), etc. In some cases, each part of theapplication may be developed by a different team with a differentlanguage.

To configure and manage container-based resources, users (e.g., networkadministrators) may interact with any suitable user interface supportedby container orchestration system 101, such as API, command lineinterface (CLI), graphical user interface (GUI) or dashboard, etc. Bymonitoring container orchestration system 101, container plugin 110 maydetect events (e.g., create, read, update and delete) associated withcontainer-based resources and translate the desired state into necessaryconfiguration of logical network elements via SDN manager 102.

In the example in FIG. 1, individual containers (not shown forsimplicity) may be grouped as pods (see “POD1” to “POD5” 141-144) andrun inside different VMs (see 131-133). Container plugin 110 mayinteract with SDN manager 102 to configure various logical networkelements connecting the containers, such as logical routers (see170-172), logical switches (see 161-162), logical switch ports (see151-154), etc. As such, container plugin 110 facilitates integrationbetween container orchestration platform 101 and SDN manager 102. Inpractice, container plugin 110 may be implemented using a bare metalserver, or a virtualized computing instance (e.g., VM or container).

Physical Implementation View

FIG. 2 is a schematic diagram illustrating a physical implementationview 200 of SDN environment 100 in FIG. 1. Depending on the desiredimplementation, SDN environment 100 may include additional and/oralternative components than that shown in FIG. 2. For example, SDNenvironment 100 may include multiple physical hosts, such as host-A210A, host-B 210B and host-C 210C that are inter-connected via physicalnetwork 204. Note that SDN environment 100 may include any number ofhosts (also known as a “host computers”, “host devices”, “physicalservers”, “server systems”, “transport nodes,” etc.), where each hostmay be supporting tens or hundreds of VMs.

Each host 210A/210B/210C may include suitable hardware 212A/212B/212Cand virtualization software (e.g., hypervisor-A 214A, hypervisor-B 214B,hypervisor-C 214C) to support various VMs 131-135. For example, host-A210A supports VM1 131 and VM5 135; host-B 210B supports VM2 132; andhost-C 210C supports VM3 133 and VM4 134. Hypervisor 214A/214B/214Cmaintains a mapping between underlying hardware 212A/212B/212C andvirtual resources allocated to respective VMs 131-135. Hardware212A/212B/212C includes suitable physical components, such as centralprocessing unit (CPU) or processor 220A/220B/220C; memory222A/222B/222C; physical network interface controllers (NICs)224A/224B/224C; and storage disk(s) 226A/226B/226C, etc.

Virtual resources are allocated to VMs 131-135 to support respectiveguest operating systems (OS) 231-235 and application(s). For example,container(s) in POD1 141 may run inside VM1 131, POD2 142 and POD4 144inside VM2 132, POD3 142 inside VM3 133, and POD5 inside VM5 135. Notethat not all VMs have to support containers in the example in FIG. 2,such as VM4 134 supporting non-containerized application(s). The virtualresources (not shown for simplicity) may include virtual CPU, guestphysical memory, virtual disk, virtual network interface controller(VNIC), etc. In practice, one VM may be associated with multiple VNICsand hardware resources may be emulated using virtual machine monitors(VMMs).

Although examples of the present disclosure refer to VMs, it should beunderstood that a “virtual machine” running on a host is merely oneexample of a “virtualized computing instance” or “workload.” Avirtualized computing instance may represent an addressable data computenode (DCN) or isolated user space instance. In practice, any suitabletechnology may be used to provide isolated user space instances, notjust hardware virtualization. Other virtualized computing instances mayinclude containers (e.g., running within a VM or on top of a hostoperating system without the need for a hypervisor or separate operatingsystem or implemented as an operating system level virtualization),virtual private servers, client computers, etc. The VMs may also becomplete computational environments, containing virtual equivalents ofthe hardware and software components of a physical computing system.

The term “hypervisor” may refer generally to a software layer orcomponent that supports the execution of multiple virtualized computinginstances, including system-level software in guest VMs that supportsnamespace containers such as Docker, etc. Hypervisors 214A-C may eachimplement any suitable virtualization technology, such as VMware ESX® orESXi™ (available from VMware, Inc.), Kernel-based Virtual Machine (KVM),etc. The term “packet” may refer generally to a group of bits that canbe transported together, and may be in another form, such as “frame,”“message,” “segment,” etc. The term “traffic” may refer generally tomultiple packets. The term “layer-2” may refer generally to a link layeror Media Access Control (MAC) layer; “layer-3” to a network or InternetProtocol (IP) layer; and “layer-4” to a transport layer (e.g., usingTransmission Control Protocol (TCP), User Datagram Protocol (UDP),etc.), in the Open System Interconnection (OSI) model, although theconcepts described herein may be used with other networking models.

Hosts 210A-C maintains data-plane connectivity with each other viaphysical network 204 to facilitate communication among VMs located onthe same logical overlay network. Hypervisor 214A/214B/214C mayimplement a virtual tunnel endpoint (VTEP) to encapsulate anddecapsulate packets with an outer header (also known as a tunnel header)identifying the relevant logical overlay network. For example,hypervisor-A 214A implements a first VTEP associated with (IPaddress=IP-A, MAC address=MAC-A). Hypervisor-B 214B implements a secondVTEP with (IP-B, MAC-B), and hypervisor-C 214C a third VTEP with (IP-C,MAC-C). Encapsulated packets may be sent via a tunnel establishedbetween a pair of VTEPs over physical network 204, over which respectivehosts are in layer-3 connectivity with one another.

Each host 210A/210B/210C may implement local control plane (LCP) agent219A/219B/219C to interact with management entities, such as SDN manager102 residing on a management plane and SDN controller 250 on a centralcontrol plane. For example, control-plane channel 201/202/203 may beestablished between SDN controller 250 and host 210A/210B/210C using TCPover Secure Sockets Layer (SSL), etc. Management entity 102/250 may beimplemented using physical machine(s), virtual machine(s), a combinationthereof, etc. One example of a SDN controller is the NSX controllercomponent of VMware NSX® (available from VMware, Inc.), which isconfigurable using SDN manager 102 in the form of an NSX manager.

Hypervisor 214A/214B/214C implements virtual switch 215A/215B/215C andlogical distributed router (DR) instance 217A/217B/217C to handle egresspackets from, and ingress packets to, corresponding VMs 131-135. In SDNenvironment 100, logical switches and logical DRs may be implemented ina distributed manner and can span multiple hosts to connect VMs 131-135.For example, logical switches that provide logical layer-2 connectivitymay be implemented collectively by virtual switches 215A-C andrepresented internally using forwarding tables 216A-C at respectivevirtual switches 215A-C. Forwarding tables 216A-C may each includeentries that collectively implement the respective logical switches.Further, logical DRs that provide logical layer-3 connectivity may beimplemented collectively by DR instances 217A-C and representedinternally using routing tables 218A-C at respective DR instances217A-C. Routing tables 218A-C may each include entries that collectivelyimplement the respective logical DRs.

Packets may be received from, or sent to, a VM or a pod running insidethe VM via a logical switch port, such as “LP1” to “LP6” 151-156 (to bediscussed further using FIG. 4). Here, the term “logical port” or“logical switch port” may refer generally to a port on a logical switchto which a virtualized computing instance is connected. A “logicalswitch” may refer generally to a software-defined networking (SDN)construct that is collectively implemented by virtual switches 215A-C inthe example in FIG. 1, whereas a “virtual switch” may refer generally toa software switch or software implementation of a physical switch. Inpractice, there is usually a one-to-one mapping between a logical porton a logical switch and a virtual port on virtual switch 215A/215B/215C.However, the mapping may change in some scenarios, such as when thelogical port is mapped to a different virtual port on a differentvirtual switch after migration of the corresponding VM (e.g., when thesource host and destination host do not have a distributed virtualswitch spanning them).

Through virtualization of networking services in SDN environment 100,logical overlay networks may be provisioned, changed, stored, deletedand restored programmatically without having to reconfigure theunderlying physical hardware architecture. A logical overlay network(also known as “logical network”) may be formed using any suitabletunneling protocol, such as Virtual eXtensible Local Area Network(VXLAN), Stateless Transport Tunneling (STT), Generic NetworkVirtualization Encapsulation (GENEVE), etc. For example, VXLAN is alayer-2 overlay scheme on a layer-3 network that uses tunnelencapsulation to extend layer-2 segments across multiple hosts.

In one example in FIG. 1, VM1 131 and VM2 132 may be located on a firstlogical layer-2 segment and connected to a first logical switch (see“LS1” 161) and a first tier-1 logical router (see “T1-LR1” 171). Inanother example, VM3 133 may be located on a second logical layer-2segment and connected to a second logical switch (see “LS2” 162) and asecond tier-1 logical router (see “T1-LR2” 172). Using a two-tiertopology, tier-1 logical routers 171-172 may be connected with eachother or an external network (not shown) via a tier-0 logical router(see “T0-LR” 170). Logical network elements 171-172, 161-162 and 151-154will be discussed further using FIG. 4.

As container technologies are more widely deployed, the risk of securitybreaches affecting containers may also increase. However, securingcontainer-based clusters is generally a complex and challenging task.For example, a comprehensive set of security policies is required toaccount for isolation at the perimeter of a cluster as well as foreast-west communication. The implementation of such policies relies onaccurate policy configuration and enforcement at differentcontainer-based resources and logical network elements of the underlyingSDN infrastructure. Further, the presence of a multitude of networkpolicies, which may be heterogenous, often complicates the managementand inspection of network connectivity among container-based resourcesand logical network elements. In some cases, a malicious third partymight exploit security loopholes to gain access to an organization'scontainer-based clusters to run malicious tasks.

Container-Based Network Policy Configuration

According to examples of the present disclosure, container-based networkpolicies may be configured in an improved manner. Examples of thepresent disclosure may be implemented as part of a single universalpoint for configuring and managing container-based network policies inSDN environment 100. As used herein, the term “container-based networkpolicy” may refer generally to a set of rule or rules that define how acontainer-based resource may interact (e.g., communicate) with anothercontainer-based resource, such as between a node and a pod, amongmultiple nodes or pods, etc. In the following, container-based networkpolicies will be exemplified using security policies (e.g., firewallrules) to manage network connectivity among container-based resources.It should be understood that other container-based network policies(e.g., IPtables rules or filters) may be configured according toexamples of the present disclosure.

In more detail, FIG. 3 is a flowchart of example process 300 forcomputer system 110 to perform container-based network policyconfiguration in SDN environment 100. Example process 300 may includeone or more operations, functions, or actions illustrated by one or moreblocks, such as 310 to 360. The various blocks may be combined intofewer blocks, divided into additional blocks, and/or eliminateddepending on the desired implementation. Example process 300 may beimplemented using any suitable “computer system,” such as hardwareand/or software capable of acting as container plugin 110, etc. In thefollowing, the term “configure” at block 310 and 340 may refer generallyto creating a new entity (i.e., container-based resource or logicalnetwork element), modifying or updating an existing entity, etc.

At 310 in FIG. 3, container plugin 110 may detect a first request (see181 in FIG. 1) to assign a container-based resource with a first labelvia container orchestration system 101. In the example in FIG. 1,container-based resource=master node 121 in cluster 120 may beassociated with logical network element=logical switch port LP1 151.Depending on the desired implementation, the request at block 310 may bedetected when master node 121 is created, or at a later time. In theformer case, container plugin 110 may also configure logical networkelement=LP1 151 at block 320.

At 330 in FIG. 3, container plugin 110 may assign LP1 151 with a secondlabel=A2 (see 184) that is mappable to a first label=A1 (see 183)assigned to master node 121 via SDN manager 102 (see 182). Depending onthe desired implementation, first label=A1 may specify a key-value pair,such as node type=master associated with master node 121. In this case,second label=A2 assigned to LP1 151 may also specify the same key-valuepair. In other words, first label=A1 and second label=A2 may belong tothe same label namespace such that network policies configured formaster node 121 will be applicable to associated LP1 151. In practice, alabel may also be referred to as tag, metadata, or the like.

At 340 and 350 in FIG. 3, in response to detecting a second request (see191) to configure a container-based network policy associated withcontainer-based resource=master node 121, container plugin 110 mayidentify logical network element=LP1 151 by mapping first label=A1assigned to master node 121 to second label=A2 assigned to LP1 151. At360, container plugin 110 may configure the container-based networkpolicy to be applicable to network traffic that is forwarded via LP1 151associated with master node 121.

Using examples of the present disclosure, network administrators mayconfigure container-based network policies via container orchestrationsystem 101 to automatically cause those policies to be implemented bycorresponding logical network elements in an efficient manner. Thisapproach should be contrasted against conventional approaches thatnecessitate network administrators to create network policies viacontainer orchestration system 101, and manually configure firewallrules for VM(s) and/or pod(s) via SDN manager 102.

As will be discussed further using FIGS. 4-6, examples of the presentdisclosure may be implemented to reduce the likelihood of securitybreaches in SDN environment 100. For example, a container-based networkpolicy in the form of a security policy (e.g., firewall rule) may beconfigured to allow network traffic from source=pod 141/142 anddestination=master node 121. Traffic from other source(s) to master node121 may be blocked. Security policies may also be configured to allow orblock network traffic between a pair of nodes, a pair of pods, a nodeand a pod, etc.

Label Assignment

FIG. 4 is a flowchart of example detailed process 400 for a computersystem to perform container-based network policy configuration in SDNenvironment 100. Example process 400 may include one or more operations,functions, or actions illustrated by one or more blocks, such as 405 to475. The various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or eliminated depending on the desiredimplementation.

At 405 in FIG. 4, container plugin 110 may monitor events on containerorchestration system 101, including configuration container-basedresources and container-based network policies. Using Kubernetes as anexample, container plugin 110 may monitor an API server supported bycontainer orchestration system 101 for any CREATE, READ, UPDATE andREMOVE events. For example, when a user creates or modifies acontainer-based resource, a corresponding CREATE or UPDATE event may bedetected by container plugin 110.

At 410, 415 and 420 in FIG. 4, in response to detecting a request toconfigure a container-based resource (denoted as “res”) via containerorchestration system 101, container plugin 110 may configure a logicalnetwork element (denoted as “lne”) by generating and sendinginstructions to SDN manager 102. Further, at 430 and 435, based on afirst label assigned to the container-based resource, container plugin110 may assign a second label to the logical network element via SDNmanager 102.

A user-configurable label may be used to “mark” or “tag” container-basedresource, such as pods and nodes for management purposes. In practice, alabel in the form of key-value pair may be attached at any suitable time(e.g., creation or post-creation) and subsequently modified. Forexample, a label may be a Kubernetes® label, Docker® label, etc. Eachcontainer-based resource may be associated with a set of multiple labelsdenoted as labels={label_i}, where label_i=(key_i, value_i) and i=1, . .. , N. To select an object assigned with a particular label_i, aselector may be defined in the form of selector=(key_i, value_i).

Some example configurations will be explained using FIG. 5, which is aschematic diagram illustrating example configuration 500 ofcontainer-based network resources and logical network elements in SDNenvironment 100.

(a) At 421 in FIG. 4, a container-based resource=namespace (NS1) may beconfigured for cluster 120 via container orchestration system 101. Inresponse, container plugin 110 may cause SDN manager 102 to configure anetwork topology for the namespace. This may involve configuring tier-1logical router=T1-LR1 171 and attaching T1-LR1 171 to a tier-0 logicalrouter=T0-LR 170. Further, a logical router port may be created onT1-LR1 171 and attached to logical switch=LS1 161. This way, amulti-tier topology may be used to isolate multiple namespacesconfigured for cluster 120. Tier-1 (T1) is referred as the lower tier,and tier-0 (T0) the upper tier. Each namespace (e.g., ns1) may have itsown objects described using a unique path (e.g.,/api/v1/namespaces/ns1).

In practice, logical switch 161-162 in FIG. 1 may be implementedcollectively by multiple hosts 210A-C, such as using virtual switches215A-C and represented internally using forwarding tables 216A-C. Tier-1logical routers 171-172 may be implemented collectively using DRinstances 217A-C and represented internally using routing tables 218A-Cat respective hosts 210A-C. Tier-1 logical routers 171-172 and tier-0logical router 170 may be implemented using an edge appliance thatprovides centralized stateful services to VMs 131-135 and pods 141-145,such as IP address assignment using dynamic host configuration protocol(DHCP), load balancing, network address translation (NAT), etc. Tier-0logical router 170 may be deployed at the edge of a data center tofacilitate north-south traffic to an external network.

(b) At 422 in FIG. 4, in response to detecting a first request (see 510)to configure container-based resource=master node 121 for cluster 120,logical network element=LP1 151 may be configured. In this case, masternode 121 may be implemented using VM1 131, and LP1 151 is a logicalswitch port of type=parent (see 511). Through container orchestrationsystem 101, master node 121 is assigned with a first label specifyingkey-value pair “nodeType: master” to indicate that its node type. Inthis case, second label specifying the same key-value pair may beassigned to LP1 151 (see 531) via SDN manager 102.

(c) At 423 in FIG. 4, in response to detecting a second request (see520) to add (POD2 142, POD4 144) to cluster 120, logical switch ports(LP2 152, LP4 154) may be configured (see 521, 522). Through containerorchestration system 101, POD2 142 and POD4 144 may be assigned with afirst label=“podType: dns” in request 520 to indicate that they aredomain name system (DNS) servers. In this case, a second labelspecifying the same key-value pair may be assigned to LP2 152 (see 532)and LP4 154 (see 533) via SDN manager 102. This way, a logical set thatincludes (POD2 142, POD4 144) may be grouped and selected using secondlabel=“podType: dns.”

Similarly, LP5 155 may be configured for POD5 145 and assigned withlabel=“podType:notDns” in a similar manner (see 534). Logical switchports LP2 152, LP4 154 and LP5 155 may be logical switch ports oftype=child because of their association with respective POD2 142, POD4144 and POD5 145. Using Kubernetes as an example, master node 121implemented by VM1 131 is responsible for management-plane andcontrol-plane tasks associated with cluster 120. Both master node 120and worker nodes 121-123 are responsible for running their owncontainerized applications. Master node 120 may implement an API server,a scheduler, a controller manager and a dashboard via which users mayperform container configuration.

Referring also to FIG. 2, both POD2 142 and POD4 144 may be executedinside VM2 132, which is assigned with label=“nodeType: notMaster”because it implements worker node 122. POD5 145 may be executed insideVM5 135, which also implements a worker node. Within a particular pod,multiple containers may share a kernel namespace for networking andstorage volume. Multiple containers may be grouped into a pod for anysuitable reasons. For example, both a first container running a webserver and a second container running a logging script for that webserver may be placed into POD5 145. This way, both the web server andits logging script may share the same storage volume to write, read,process and export logs. Containers within a pod may communicate usinginter-process communications (IPC).

Example Container-Based Network Policy Configuration

According to examples of the present disclosure, container-based networkpolicies may be configured for container-based resources and associatedlogical network elements based on labels in the same label namespace.Examples of the present disclosure may be implemented as part of asecurity framework for one-stop security policy solution forcloud-native applications. This way, the configurability of networkpolicies and security defense for container-based resources may beimproved in SDN environment 100. In the following, blocks 440-475 willbe explained using FIG. 6, which is a schematic diagram illustratingfirst example 600 of container-based network policy configuration in SDNenvironment 100.

Conventionally, Kubernetes policy solutions have a significantlimitation in that only a group of pods may be selected to apply aparticular network policy, while the underlying infrastructure (e.g.,VM) and network (e.g., logical routers, logical switches and logicalports) are left unconsidered. Consequently, users have to resort toseparate, additional solutions for isolation. For example, in acloud-native landscape, VM is no longer a first-class citizen from anetworking perspective, in that network plugins for Kubernetes are notrequired to manage VM networks, and most plugins do not. Consequently,coupled with the network policy limitation mentioned above, users mayneed to resort to setting up IP table rules on individual VMs, andfirewall rules on their cloud providers to implement VM-to-VM andVM-to-pod traffic isolation. This results in management of networkpolicies that is dispersed and ad hoc, which is inefficient andundesirable.

At 405, 440 and 445 in FIG. 4, container plugin 110 may monitorcontainer orchestration system 101 for events and detect a request toconfigure a container-based network policy for one container-basedresource or a group of multiple container-based resources. The requestmay be initiated by a user (e.g., IT and/or cluster administrator)responsible for creating and maintaining Kubernetes clusters andunderlying SDN infrastructure. In practice, the network policy may bedefined to secure and isolate container-based resources (e.g., nodes andpods). The network policy may be configured to establish the contour ofa tenant's networking capabilities, and at the same time reduce thesurface exposed to security vulnerabilities.

Referring also to FIG. 6, a network policy may be specified in request610 using custom resource definition (CRD). Request 610 may specifyselector(s) to select container-based resource(s) to which the networkpolicy is appliable. At 611-612, for example, request 610 includes a VMselector to select node(s) implemented using VM(s), such as node(s) withlabel=“nodeType: master.” At 613-614, request 610 includes a podselector to select pod with label=“podType: dns.” Any additional and/oralternative selector(s) may be used, such as namespace selector toselect namespace(s). Each selector may specify the exact label to bematched, a prefix or “contains” string matching with names. For example,a VM selector specifying “contains: worker” may be matched to label thatincludes the string “worker.”

Request 610 may include other policy-related information, such as packetheader fields (e.g., protocol=TCP and port number=443) to which thefirewall rule is applicable, priority level (e.g., top or bottom),classless inter-domain routing (CIDR) information (e.g., 10.10.10.0/24).In the example in FIG. 6, the network policy may be used to definewhitelist rules to allow traffic matching a set of match fields. Thisway, all ingress and/or egress traffic will be dropped unless allowed bythe network policy. In practice, the network policy may also be used todefine blacklist rules to block traffic matching a set of match fields.

At 450, 455 and 460 in FIG. 4, in response to detecting request 610,container plugin 110 may identify logical network element(s) associatedwith the selected container-based resource(s). In the example in FIG. 6,request 610 specifies a firewall rule that is applicable to TCP trafficwith port number 443 from a source pod to a destination VM. At 620 inFIG. 6, container plugin 110 may identify destination=VM1 131 based onlabel=“nodeType: master” and configure a destination logical port groupthat includes LP1 151. At 630, container plugin 110 may identifysource=(POD2 142, POD4 144) based on label=“podType: dns” and configurea source logical port group that includes (LP2 152, LP4 154). Theconfiguration at blocks 450-455 may involve container plugin 110generating and sending instructions to SDN manager 102.

At 465 and 470 in FIG. 4, container plugin 110 may generate and sendinstructions to SDN manager 102 to configure the network policy. At 475,the network policy may be applied using hosts 110A-C to allow or blocktraffic to LP1 151 connected to VM1 131. In the example in FIG. 6,firewall rule 640 specifies action=ALLOW to allow packets from anymember of source group=(LP2 152, LP4 154) to destination group=(LP1 151)for protocol=TCP and port number=443.

Depending on the desired implementation, firewall rule 640 may beapplied using a distributed firewall (DFW) engine to filter trafficbeing forwarded via a logical port. For example, firewall rule 640 maybe applied at a first DFW engine 651 to filter ingress (i.e., incoming)traffic at LP1 151 associated with VM1 131. Additionally oralternatively, firewall rule 640 may be applied at a second DFW engine652 to filter egress (i.e., outgoing) traffic at LP2 152 connected toPOD2 142, as well as a third DFW engine 653 to filter egress traffic atLP4 154. Firewall rule 640 may also be applied at DFW engine 654 toblock egress traffic from source=LP5 155 to destination=LP1 151 becauseassociated POD5 145 is not tagged with “podType: dns” (see 534).

Using examples of the present disclosure, container-based networkpolicies may be namespaced to facilitate the mapping between (a)container-based resource(s) managed by container orchestration system101 and (b) logical network element(s) managed by SDN manager 102. Inresponse to detecting a CREATE event with policy specification,container plugin 110 computes the required firewall rules to be createdand finds which firewall section to place the firewall rules. Toconfigure the firewall rules, container plugin 110 may invoke an APIsupported by SDN manager 102. Leveraging the realization stateinformation reported by SDN manager 102, container plugin 110 maypublish the state information once it becomes available. This way, theuser may be informed of the success or failure in realizing the firewallrules in the datapath via container orchestration system 101. Theframework may be configured to offer users the capability to definecomprehensive security policies that are applicable to variouscomponents of infrastructure (e.g., VMs and pods), network topologyformed by various logical network elements (e.g., logical ports, logicalswitches and logical routers), and container-based resources (e.g.,clusters, nodes and namespaces).

Using examples of the present disclosure, the risk of hindering networkdebuggability as a result of lack of centralized management of varioussecurity policies may be reduced. Users may plug and play differenttechnologies, such as Kubernetes network policy for layer-3 and layer-4isolation for pods, and Cilium for layer 7 and cloud provider's firewallfor infrastructure level isolation. Cilium is an open-source softwarefor securing network connectivity between application services. Wherepossible, legacy firewall rules may be automatically converted tonetwork policies that support automatic mapping from container-basedresource(s) to logical network element(s) for the purpose of centralizedmanagement.

Container-Based Connectivity Checks

In practice, various network issues that affect the performance oflogical network elements and corresponding container-based resources mayoccur in SDN environment 100. Conventionally, however, it may bechallenging to perform network diagnosis using existing tools. In somecases, users may need to exhaust all tracing or monitoring tools topinpoint the cause of network issues, such as packet drop, etc. Forexample, ping and traceroute are Linux utilities for testing networkconnectivity for debugging purposes. Due to the scale and complexity ofthe underlying logical network topology, such utilities are ofteninadequate for troubleshooting and debugging purposes. This may in turnincrease system downtime in SDN environment 100 due to undiagnosedperformance issues.

According to examples of the present disclosure, network troubleshootingand diagnosis may be improved by performing connectivity checks betweena pair of container-based resources and corresponding logical networkelements. In practice, a container-based network connectivity check toolmay be built upon the container-based network policy configurationexplained using FIG. 1 to FIG. 6. Using Kubernetes as an example,container-based network connectivity checks may be used for inspectingKubernetes security policies that interact with packets duringend-to-end transfers. In this case, examples of the present disclosuremay be implemented to identify active security policies that may resultin packet drops affecting network flows.

In more detail, FIG. 7 is a flowchart of example process 700 forcomputer system 110 to perform container-based network policyconfiguration in SDN environment 100. Example process 700 may includeone or more operations, functions, or actions illustrated by one or moreblocks, such as 710 to 752. The various blocks may be combined intofewer blocks, divided into additional blocks, and/or eliminateddepending on the desired implementation. Example process 700 may beimplemented using any suitable “computer system,” such as hardwareand/or software capable of acting as container plugin 110, etc.

At 710 in FIG. 7, container plugin 110 may detect, from containerorchestration system 101, a request for a connectivity check between afirst container-based resource (e.g., POD4 144) and a secondcontainer-based resource (e.g., POD3 143). At 720, a first logicalnetwork element (e.g., LP4 154) associated with the firstcontainer-based resource and a second logical network element (e.g., LP3153) associated with the second first container-based resource may beidentified. At 730 in FIG. 7, a connectivity check packet may beinjected at the first logical network element to cause the connectivitycheck packet to be forwarded towards the second logical network element.

At 740 in FIG. 7, container plugin 110 may receive report informationassociated with intermediate logical network element(s) that are locatedalong a path between the first logical network element (e.g., LP4 154)and the second logical network element (e.g., LP3 153). At 750, based onthe report information, a connectivity status associated with the firstcontainer-based resource (e.g., POD4 144) and the second container-basedresource (e.g., POD3 143) may be determined.

Depending on the desired implementation, block 750 may includeidentifying a container-based network policy that is applicable to theconnectivity check packet (see 752). For example, the container-basednetwork policy may be identified based on labels assigned to respectivecontainer-based resources (e.g., POD3 143 and POD4 144 and) and/orlogical network elements (e.g., LP3 153 and LP4 154). As will bedescribed below, the container-based network policy may be a firewallrule that is configured to allow or block communication between thecontainer-based resources.

Although exemplified using pods, it should be understood thatcontainer-based connectivity checks may be performed for the followingpairs of container-based resources: node and pod, pair of nodes, pod andservice, pod and ingress, etc. The pair of container-based resources forwhich a connectivity check is initiated may belong to the same namespaceor different namespaces. Depending on the desired implementation, thepair of container-based resources may belong to the same cluster ordifferent clusters. In the following, some examples will be discussedusing FIG. 4, FIG. 8, FIG. 9 and FIG. 10.

(a) Network Policy Configuration

According to blocks 405-435 in FIG. 4, container plugin 110 mayconfigure and label associated logical network elements by generatingand sending instructions (e.g., API calls) to SDN manager 102. Variousexample requests are shown at 810 in FIG. 8, which is a schematicdiagram illustrating example 800 of network policy configuration priorto a container-based connectivity check in SDN environment 100.

At 811 in FIG. 8, based on a first request to add namespace=NS1 tocluster 120, container plugin 110 may configure T1-LR1 171 and logicalswitch LS1 161. At 812, based on a second request to configurenamespace=NS2, container plugin 110 may configure another T1-LR2 172 andLS2 162. At 813, based on a third request to add POD2 142 and POD4 144to namespace=NS1, respective LP2 152 and LP4 154 may be configured onLS1 161. At 814, based on a fourth request to add POD3 143 tonamespace=NS2, LP3 153 may be configured on LS2 162 and connected toPOD3 143 supported by VM3 133.

In the example in FIG. 8, POD3 143 may implement a web server and taggedwith label=“app: server” (see 815). POD4 144 may implement a clientserver and tagged with label=“app: client” (see 814). In contrast, POD2142 may be tagged with label=“app: notClient” (see 813) to indicate itis not a client server. As such, LP3 153 may be assigned withlabel=“app: server” (see 821), LP4 154 with label=“app: client” (see822) and LP2 152 with label=“app: notClient” (see 823).

According to blocks 440-475, container plugin 110 may configure acontainer-based network policy for container-based resource(s) andassociated logical network elements via SDN manager 102. For example inFIG. 8, consider a request (see 830) to configure a network policy(name=“allow-client”) to allow traffic to pods tagged with label=“app:server” (see 831) only from pods tagged with label=“app: client” (see832). At 841, a destination group=LP3 153 may be created to collectlogical port(s) tagged with “app: server.” At 842, a source group=LP4154 may be created to collect logical port(s) tagged with “app: client.”

Firewall rule 850 may be created to allow TCP 80 traffic from the sourcegroup (i.e., LP4 154 connected to POD4 144) to the destination group(i.e., LP3 153 connected to POD3 143). This way, traffic from any sourcethat does not belong to the source group will be blocked, such as fromLP2 152 tagged with “app: notClient” to LP3 153. Firewall rule 850 maybe applied to ingress traffic received at destination LP3 153 using DFWengine 863. Additionally or alternatively, firewall rule may be appliedto egress traffic forwarded via LP4 154 using DFW engine 862 and/or LP2152 using DFW engine 861. In practice, DFW engines may be implementedusing hypervisors 114A-C of respective hosts 110A-C.

(b) Connectivity Check for POD3 and POD4

FIG. 9 which is a schematic diagram illustrating first example 900 ofcontainer-based connectivity check in SDN environment 100. In practice,container plugin 110 may monitor events on container orchestrationsystem 101 periodically, particularly a user's request forcontainer-based connectivity checks.

At 910 in FIG. 9, container plugin 110 may detect a first trace requestto initiate a first connectivity check between POD4 144 and POD3 143.Trace request 910 may be a specification with the required informationfor a network flow to be analyzed. For example, source=POD4 144 innamespace=NS1 may be selected using a pod selector identifyinglabel=“app: client” (see 911). Destination=POD3 143 in namespace=NS2 maybe selected using a pod selector identifying label=“app: server” (see912).

In response to detecting trace request 910, container plugin 110 mayselect source=LP4 154 based on label=“app: client” (see 822) assigned toLP4 154 in the example in FIG. 8. Similarly, destination=LP3 153 may beselected based on label=“app: server” (see 821) assigned to LP3 153.Container plugin 110 may also translate trace request 910 to tupleinformation (e.g., source IP address, source port number, destination IPaddress, destination port number and protocol) to be specified by theconnectivity check packet (labelled “X”).

At 920 in FIG. 9, the connectivity check packet may be injected at LP4154 for forwarding towards LP3 153 via a datapath that includes LS1 161,T1-LR1 171, T0-LR 170, T1-LR2 172 and LS2 162 (“intermediate logicalnetwork elements”). In practice, any suitable approach may be used togenerate and inject connectivity check packets. For example, a toolcalled Traceflow (available from VMware, Inc.) may be extended to injecta connectivity check packet (e.g., Traceflow packet) for cross-cloudconnectivity checks. To perform a connectivity check between LP4 154 andLP3 153, connectivity check packet 920 may be injected by SDN manager102 at host-B 210B for transmission to host-C 210C. Connectivity checkpacket 920 may include an inner packet that is encapsulated with anouter header. The inner packet may be addressed from POD4 144 (e.g.,source IP-POD4) to POD3 143 (e.g., destination IP-POD3). The outerheader may of the connectivity check packet may include addressinformation of source host-B 210B (e.g., VTEP IP-B) and destinationhost-C 210C (e.g., VTEP IP-C).

Connectivity check packet 920 may traverse the logical network topology,potentially vising multiple transport nodes. Connectivity check packet920 may be configured to cause intermediate logical network element togenerate and send report information to SDN manager 102 and/or containerplugin 110. Next, container plugin 110 may obtain report informationfrom the intermediate logical network elements, either directly orindirectly via SDN manager 102. For example, container plugin 110 mayinteract with SDN manager 102 using hypertext transfer protocol (HTTP)requests, such as PUT and GET to obtain the necessary information. Thereport information may specify (ID, STATUS) at a particular logicalnetwork element. The ID may include any suitable information identifyingits sender, such as a unique ID, name, element type, element sub-type,whether the sender is a tier-0 or tier-1 logical router (whereapplicable), any combination thereof. The ID may also indicate. The“STATUS” may be “RECEIVED,” “FORWARDED,” “DELIVERED,” “DROPPED,” etc.

At 930 in FIG. 9, the report information may specify the followingstatus information: “INJECTED” at LP4 154 (see 931),“RECEIVED+FORWARDED” by LS1 (see 932), T1-LR1 171 (see 933), T0-LR 170(see 934), T1-LR2 172 (see 935) and LS2 162 (see 936). The reportinformation also indicates that the connectivity check packet isDELIVERED (see 937) to destination LP3 153. In this case, containerplugin 110 may determine that LP4 154 has connectivity with LP3 153.

At 940 in FIG. 9, container plugin 110 may generate a trace result thatidentifies a network policy that is applicable to connectivity checkpacket 920 from LP4 154 to LP3 153. In this case, container plugin 110may identify the network policy (“allow-client”) configured in theexample in FIG. 8 based on label (or tag or metadata) associated withthe firewall rule traversed, such as “networkPolicy: allow-client”assigned to firewall rule 850.

Trace result 940 may specify a list of container-based resourcestraversed by the connectivity check packet, i.e., source POD4 144 innamespace=NS1, network policy=“allow-client” that configured for NS1 anddestination POD3 143 in namespace=NS2. Trace result 940 may also specifya list of logical network elements traversed by the connectivity checkpacket, i.e., LP4 154, LS1 161, T1-LR1 171, T0-LR 170, T1-LR2 172, LS2162 and LP3 153. This way, container-based network policies interactingwith end-to-end packet flows may be examined to identify any networkconnectivity issues.

(c) Connectivity Check for POD2 and POD3

FIG. 10 which is a schematic diagram illustrating second example 1000 ofcontainer-based connectivity check in SDN environment 100. At 1010 inFIG. 10, container plugin 110 may detect a second trace request toinitiate a connectivity check between POD2 142 and POD3 143. Tracerequest 1010 may select source=POD2 142 in namespace=NS1 using a podselector with label=“app: notClient” (see 1011). Destination=POD3 143 innamespace=NS2 may be selected using a pod selector identifyinglabel=“app: server” (see 1012). In response to detecting trace request1010, container plugin 110 may select source=LP2 152 based onlabel=“app: client” (see 823) assigned to LP2 152. Similarly,destination=LP3 153 may be selected based on label=“app: server” (see821) assigned to LP3 153.

At 1020 in FIG. 10, a second connectivity check packet (labelled “Y”)may be injected at LP2 152 for forwarding towards LP3 153 via a datapaththat includes LS1 161, T1-LR1 171, T0-LR 170, T1-LR2 172 and LS2 162(“intermediate logical network elements”). At 1030, container plugin 110may obtain report information specifying the following: “INJECTED” atLP2 152 (see 1031), “RECEIVED+FORWARDED” by LS1 (see 1032), T1-LR1 171(see 1033), T0-LR 170 (see 1034), T1-LR2 172 (see 1035) and LS2 162 (see1036). The report information also indicates that the connectivity checkpacket is DROPPED (see 1037) at LP3 153. In this case, it is determinedthat LP2 152 has no connectivity with LP3 153.

At 1040 in FIG. 10, container plugin 110 may generate a trace resultthat identifies a network policy that is applicable to connectivitycheck packet 1020. In this case, container plugin 110 may identify thenetwork policy (“allow-client”) configured in the example in FIG. 8based on label (or tag or metadata) associated with the firewall ruletraversed, such as “networkPolicy: allow-client” assigned to firewallrule 860 in FIG. 8). Firewall rule 860 is configured based on request830 to block traffic to LP3 153 from any other source (e.g., LP2 152)that does not belong to source group={LP4 154}, nor tagged withlabel=“app: client.”

Trace result 1040 may specify a list of container-based resourcestraversed by the connectivity check packet, i.e., source POD4 144 innamespace=NS1, network policy=“allow-client” that configured for NS1 anddestination POD2 142 in namespace=NS2. Trace result 1040 may specify alist of logical network elements traversed by the connectivity checkpacket, i.e., LP2 152, LS1 161, T1-LR1 171, T0-LR 170, T1-LR2 172, LS2162 and LP3 153.

Computer System

The above examples can be implemented by hardware (including hardwarelogic circuitry), software or firmware or a combination thereof. Theabove examples may be implemented by any suitable computing device,computer system, etc. The computer system may include processor(s),memory unit(s) and physical NIC(s) that may communicate with each othervia a communication bus, etc. The computer system may include anon-transitory computer-readable medium having stored thereoninstructions or program code that, when executed by the processor, causethe processor to perform process(es) described herein with reference toFIG. 1 to FIG. 10. For example, the instructions or program code, whenexecuted by the processor of the computer system, may cause theprocessor to perform network troubleshooting according to examples ofthe present disclosure.

The techniques introduced above can be implemented in special-purposehardwired circuitry, in software and/or firmware in conjunction withprogrammable circuitry, or in a combination thereof. Special-purposehardwired circuitry may be in the form of, for example, one or moreapplication-specific integrated circuits (ASICs), programmable logicdevices (PLDs), field-programmable gate arrays (FPGAs), and others. Theterm ‘processor’ is to be interpreted broadly to include a processingunit, ASIC, logic unit, or programmable gate array etc.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or any combination thereof.

Those skilled in the art will recognize that some aspects of theembodiments disclosed herein, in whole or in part, can be equivalentlyimplemented in integrated circuits, as one or more computer programsrunning on one or more computers (e.g., as one or more programs runningon one or more computing systems), as one or more programs running onone or more processors (e.g., as one or more programs running on one ormore microprocessors), as firmware, or as virtually any combinationthereof, and that designing the circuitry and/or writing the code forthe software and or firmware would be well within the skill of one ofskill in the art in light of this disclosure.

Software and/or other instructions to implement the techniquesintroduced here may be stored on a non-transitory computer-readablestorage medium and may be executed by one or more general-purpose orspecial-purpose programmable microprocessors. A “computer-readablestorage medium”, as the term is used herein, includes any mechanism thatprovides (i.e., stores and/or transmits) information in a formaccessible by a machine (e.g., a computer, network device, personaldigital assistant (PDA), mobile device, manufacturing tool, any devicewith a set of one or more processors, etc.). A computer-readable storagemedium may include recordable/non recordable media (e.g., read-onlymemory (ROM), random access memory (RAM), magnetic disk or opticalstorage media, flash memory devices, etc.).

The drawings are only illustrations of an example, wherein the units orprocedure shown in the drawings are not necessarily essential forimplementing the present disclosure. Those skilled in the art willunderstand that the units in the device in the examples can be arrangedin the device in the examples as described, or can be alternativelylocated in one or more devices different from that in the examples. Theunits in the examples described can be combined into one module orfurther divided into a plurality of sub-units.

We claim:
 1. A method for a computer system to perform container-basedconnectivity check in a software-defined networking (SDN) environment,wherein the method comprises: detecting, by the computer system which isconfigured as an interface between a container orchestration system anda SDN manager, a request for a connectivity check between a firstcontainer-based resource and a second container-based resource;identifying, by the interface, a first logical network elementassociated with the first container-based resource and a second logicalnetwork element associated with the second first container-basedresource; causing, by the interface, injecting of a connectivity checkpacket at the first logical network element to cause the connectivitycheck packet to be forwarded towards the second logical network element;obtaining, by the interface, report information associated with one ormore intermediate logical network elements located along a path that istraversed by the connectivity check packet between the first logicalnetwork element and the second logical network element; and based on thereport information, determining, by the interface, a connectivity statusassociated with the first container-based resource and the secondcontainer-based resource.
 2. The method of claim 1, wherein determiningthe connectivity status comprises: based on the report information,identifying a container-based network policy that is applicable to theconnectivity check packet.
 3. The method of claim 2, wherein identifyingthe container-based network policy comprises: identifying thecontainer-based network policy based on at least one of: (a) firstlabels assigned respectively to the first container-based resource andsecond container-based resource; and (b) second labels assignedrespectively to the first logical network element and second logicalnetwork element, wherein the second labels are mappable to the firstlabels.
 4. The method of claim 2, wherein determining the connectivitystatus comprises: based on the report information, identifying thecontainer-based network policy as a firewall rule that is configured toblock communication from the first container-based resource to thesecond container-based resource and cause the connectivity check to bedropped.
 5. The method of claim 2, wherein identifying thecontainer-based network policy comprises: based on the reportinformation, identifying the container-based network policy as afirewall rule that is configured to allow communication from the firstcontainer-based resource to the second container-based resource andcause the connectivity check to be forwarded.
 6. The method of claim 2,further comprising: generating and sending a response to the containerorchestration system, wherein the response specifies the connectivitycheck status and the container-based network policy.
 7. The method ofclaim 1, wherein obtaining the report information comprises: obtainingthe report information that is generated by intermediate logical networkelements that connect the first logical network element and the secondlogical network element and that include one or more of: a logicalswitch port, a logical switch, a tier-1 logical router, and a tier-0logical router.
 8. A non-transitory computer-readable storage mediumthat includes a set of instructions which, in response to execution by aprocessor of a computer system, cause the processor to perform a methodof container-based connectivity check in a software-defined networking(SDN) environment, wherein the method comprises: detecting, by thecomputer system which is configured as an interface between a containerorchestration system and a SDN manager, a request for a connectivitycheck between a first container-based resource and a secondcontainer-based resource; identifying, by the interface, a first logicalnetwork element associated with the first container-based resource and asecond logical network element associated with the second firstcontainer-based resource; causing, by the interface, injecting of aconnectivity check packet at the first logical network element to causethe connectivity check packet to be forwarded towards the second logicalnetwork element; obtaining, by the interface, report informationassociated with one or more intermediate logical network elementslocated along a path that is traversed by the connectivity check packetbetween the first logical network element and the second logical networkelement; and based on the report information, determining, by theinterface, a connectivity status associated with the firstcontainer-based resource and the second container-based resource.
 9. Thenon-transitory computer-readable storage medium of claim 8, whereindetermining the connectivity status comprises: based on the reportinformation, identifying a container-based network policy that isapplicable to the connectivity check packet.
 10. The non-transitorycomputer-readable storage medium of claim 9, wherein identifying thecontainer-based network policy comprises: identifying thecontainer-based network policy based on at least one of: (a) firstlabels assigned respectively to the first container-based resource andsecond container-based resource; and (b) second labels assignedrespectively to the first logical network element and second logicalnetwork element, wherein the second labels are mappable to the firstlabels.
 11. The non-transitory computer-readable storage medium of claim9, wherein determining the connectivity status comprises: based on thereport information, identifying the container-based network policy as afirewall rule that is configured to block communication from the firstcontainer-based resource to the second container-based resource andcause the connectivity check to be dropped.
 12. The non-transitorycomputer-readable storage medium of claim 9, wherein identifying thecontainer-based network policy comprises: based on the reportinformation, identifying the container-based network policy as afirewall rule that is configured to allow communication from the firstcontainer-based resource to the second container-based resource andcause the connectivity check to be forwarded.
 13. The non-transitorycomputer-readable storage medium of claim 9, wherein the method furthercomprises: generating and sending a response to the containerorchestration system, wherein the response specifies the connectivitycheck status and the container-based network policy.
 14. Thenon-transitory computer-readable storage medium of claim 8, whereinobtaining the report information comprises: obtaining the reportinformation that is generated by intermediate logical network elementsthat connect the first logical network element and the second logicalnetwork element and that include one or more of: a logical switch port,a logical switch, a tier-1 logical router, and a tier-0 logical router.15. A computer system, comprising: a processor; and a non-transitorycomputer-readable medium having stored thereon instructions that, inresponse to execution by the processor, cause the processor to: detect,by the computer system which is configured as an interface between acontainer orchestration system and a SDN manager, a request for aconnectivity check between a first container-based resource and a secondcontainer-based resource; identify, by the interface, a first logicalnetwork element associated with the first container-based resource and asecond logical network element associated with the second firstcontainer-based resource; cause, by the interface, injection of aconnectivity check packet at the first logical network element to causethe connectivity check packet to be forwarded towards the second logicalnetwork element; obtain, by the interface, report information associatedwith one or more intermediate logical network elements located along apath that is traversed by the connectivity check packet between thefirst logical network element and the second logical network element;and based on the report information, determine, by the interface, aconnectivity status associated with the first container-based resourceand the second container-based resource.
 16. The computer system ofclaim 15, wherein the instructions that cause the processor to determinethe connectivity status cause the processor to: based on the reportinformation, identify a container-based network policy that isapplicable to the connectivity check packet.
 17. The computer system ofclaim 16, wherein the instructions that cause the processor to identifythe container-based network policy cause the processor to: identify thecontainer-based network policy based on at least one of: (a) firstlabels assigned respectively to the first container-based resource andsecond container-based resource; and (b) second labels assignedrespectively to the first logical network element and second logicalnetwork element, wherein the second labels are mappable to the firstlabels.
 18. The computer system of claim 16, wherein the instructionsthat cause the processor to determine the connectivity status cause theprocessor to: based on the report information, identify thecontainer-based network policy as a firewall rule that is configured toblock communication from the first container-based resource to thesecond container-based resource and cause the connectivity check to bedropped.
 19. The computer system of claim 16, wherein the instructionsthat cause the processor to identify the container-based network policycause the processor to: based on the report information, identify thecontainer-based network policy as a firewall rule that is configured toallow communication from the first container-based resource to thesecond container-based resource and cause the connectivity check to beforwarded.
 20. The computer system of claim 16, wherein the instructionsfurther cause the processor to: generate and send a response to thecontainer orchestration system, wherein the response specifies theconnectivity check status and the container-based network policy. 21.The computer system of claim 15, wherein the instructions that cause theprocessor to obtain the report information cause the processor to:obtain the report information that is generated by intermediate logicalnetwork elements that connect the first logical network element and thesecond logical network element and that include one or more of: alogical switch port, a logical switch, a tier-1 logical router, and atier-0 logical router.